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Eye-controlled contact lenses

Biomechanical engineers have created a robotic lens that allows the wearer to focus on an image through eye movements, such as a double blink.

The researchers, from the University of California San Diego and Harbin Institute of Technology, created what they called a Biometric Soft Lens, made mainly of multiple polymer films.

Their experiments showed that electrical signals generated by eye movements change the focal length of the lens, allowing it to effectively zoom in.

“Soft lens, made from different stimuli-responsive materials, have demonstrated superior performance, compared to conventional glass lens,” says their research paper, published in Advanced Functional Materials.

“The system developed in the current study has the potential to be used in visual prostheses, adjustable glasses, and remotely operated robotics in the future.”

The polymer lens is controlled by five electrodes, which use electrical signals generated by eye movements, called electrooculography (EOG) signals.

A double blink created enough of an EOG signal for the soft lens to expand its surface area and reduce its thickness, which in turn caused a change to its focal point.

The paper says the relative change of focal length of the lens could be as much as 32% – although this only brought it comparable to that of human eyes.

As well as potential uses in soft robotics, the lens may have applications for visualising physiological principles for biology and medicine.

Previous studies have demonstrated soft lenses that needed to be controlled manually or by pre-written programmes. Six years ago, UCSD researchers developed telescopic contact lenses that required a pair of Samsung 3D glasses to switch to telescopic vision.